The Seventh Circuit has started 2012 off with a significant class certification opinion.  Messner v. Northshore Univ. Healthsystem, No. 10-2514, 2012 U.S. App. LEXIS 731 (7th Cir. Jan. 13, 2012) was an antitrust case alleging that a merger of two hospitals violated federal antitrust laws, but the opinion speaks to several broader issues regarding